create a new folder on your memstick called ms0:\PSP\GAME150 and place the MAMe4all folder, etc. in it.

MAME4allPSP won't run under the 4.01 kernel. So you need to create a separate GAME150 folder for all your games that need to run under 150 Kernel.

PSPfiler requires this as well. Some older homebrews like this require the 1.50 Kernel, so you need to either: create a GAME150 folder next to the GAME folder and place these 1.50 only games in it, or in the recovery menu - enable the 1.50 Kernel as the default - in which case you don't need the extra GAME150 folder, but some newer games might not run right under the 1.50 Kernel as the default.

I have both a PSP Phat & slim with 4.01m33 on both.I have MAME4ALL v4.9r2 16112007 and it works fine on both.I don't think you need the 1.5 firmware to run it.

After downloading, inside the zip you'll find 4 files, unzip the one named: PSP_MAME4ALL_v4.9r2_Hires_by_TTYman_-_16112007.zipInside there you'll see a folder named: psp_mame4all_v4.9r2Copy it and all subfolders to you PSP memory stick in the GAME4xx folderNow go back and find the folder named: psp_mame4all_v4.9r2-usermodeuse the eboot.pbp file in that folder to replace the one you just copied to the memorystick in the mame4all folder.

The roms need to be zipped and in the MAME 0.34 format since mame4all is base on v0.34